Uncertainties in the diagnosis and treatment of pulmonary arterial hypertension.

The availability of new treatments for patients with pulmonary arterial hypertension has increased awareness and interest in the medical community for pulmonary vascular diseases in general. Many uncertainties exist, however, regarding the diagnosis and treatment of patients with pulmonary arterial hypertension that are particularly pertinent for the management of patients with idiopathic pulmonary arterial hypertension and pulmonary hypertension associated with underlying diseases. This review highlights controversial issues around the definition and diagnosis of pulmonary hypertension, the interpretation of hemodynamic variables, and the interpretation of clinical responsiveness to chronic therapies. In addition, we propose guidelines applicable to the conduct of new therapeutic trials in pulmonary arterial hypertension, which aim to provide greater confidence in the efficacy and safety of new treatments currently under development.